Abstract: Bilingual Latino high school students who studied Spanish as an academic subject demonstrated a heightened awareness of how to use their two languages as complementary resources in school and professional settings. A case study traces one student's literacy development in Spanish over four years and her ability to use it as a resource in her development of academic English in a college setting. Analysis of videotaped classroom presentations illustrates how an instructor's acceptance of student codeswitching, along with his selective use of codeswitching in his own interaction with students, created an academic environment that validated students' home language patterns but at the same time maintained Spanish as the classroom norm. Students' performance on national Spanish language tests, as well as their enrollment in college preparatory classes, suggest areas for further research on high school retention and preparation for postsecondary education.